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What this video covers

Engine oil turning black shortly after an oil change on a Universal M35 with 3,500 hours is normal, not a sign of engine failure.0:52 Nigel Calder explains that carbon buildup inside a high-hour engine, combined with blow-by past worn piston rings, continuously darkens fresh oil.1:07 Sailboat engines are especially prone to this because their typical duty cycle — low load, short runs — accelerates carbon formation.0:58 Even a brand-new engine will show some black in the oil after roughly 50 hours; the older and more worn the engine, the faster the darkening occurs.1:20 The 1995 Catalina 36 in question runs smoothly, shows no oil consumption, and produces clean exhaust, all of which confirm the engine is functioning correctly.0:40 Calder's advice: do nothing.1:24 No further oil changes, no additives, no investigation — the oil color alone is not a problem requiring a fix.1:30

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